This invention relates to addition interpolymers especially useful in coating compositions. More particularly, this invention relates to addition interpolymers prepared from isobornyl (meth)acrylate which contain silane groups which interpolymers can be included in coating compositions as the main film former. The resultant coating compositions are curable at low temperatures and are especially useful in the automotive refinish area. The coating compositions are also useful for automotive original equipment finishes where reduced curing temperatures are desired, for example from 150 to 180 degrees F. (65 to 85 degrees C.).
The coatings industry has been extensively involved in energy conservation activity for a number of years. Most coating compositions require an elevated temperature of at least about 120 degrees Celsius (degrees C.) for curing purposes. This represents a considerable expenditure of energy. Additionally, coating compositions which are intended for use in the automotive refinish area oftentimes are applied under conditions such that the aforementioned elevated temperatures are not available for curing purposes. Ideally, the coating composition which can be cured at relatively low temperatures, for example, below about 82 degrees C., and preferably at ambient temperature, would be most useful. Previous attempts to develop such coating compositions have resulted in compositions which were extremely slow to cure and/or produce films which were deficient in one physical property or another.
In addition to there being a need for a coating composition which is capable of curing at a low temperature, it is also desirable that such compositions be non-isocyanate based.
In accordance with this invention, an ambient temperature moisture-curable coating composition has been developed which has an acceptable rate of cure and which, upon curing, produces a film having excellent appearance and durability properties, particularly increased hardness and increased gloss, and surprisingly excellent distinctness of image (DOI). A film having a high degree of distinctness of image when viewed from a direction close to the normal to the surface and under, for example, a light fixture such as a fluorescent light fixture having a cross-hatch grid in front of the bulb, exhibits a reflected image of the lighted fixture in the film which appears clear and sharply distinct and which appears to originate deep in the film.